listplaylists command created + test.

LibMpcTest/Tests/PlaylistsCommandsTest.cs

@@ -0,0 +1,22 @@
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+using Xunit;
+using LibMpc;
+using System.Linq;
+
+namespace LibMpcTest
+{
+    public partial class LibMpcTest
+    {
+        [Fact]
+        public async Task ListPlaylistsTest()
+        {
+            var response = await Mpc.SendAsync(new Commands.Playlists.Stored.ListPlaylists());
+
+            TestOutput.WriteLine($"ListPlaylistsTest Result:");
+            TestOutput.WriteLine(JsonConvert.SerializeObject(response, Formatting.Indented));
+
+            Assert.True(response.Response.Body.Count().Equals(3));
+        }
+    }
+}